Material: Plastic Size: 15 * 5.5 * 4cm Color: Black Caliber: 38-43 mm Flat circle of the M circle: 34-38.5 mm compatible with 32-50 mm telescope S-circle curve circle: 31-34 mm compatible with astronomy and telescopes with small openings Two circles superimposed: 26-28mm compatible with microscope and astronomy Quantity: 1 piece Package Contents: 1 * Universal Telescope Bracket 1. Align the eyepiece with your phone camera. It takes less than 1 minute to connect the phone to the optical instrument and get clear pictures. 2. The universal phone adapter bracket is compatible with eyepieces with an outer diameter of 38-43 mm and can be mounted on most binoculars, monoculars, telescopes, spotting scopes, microscopes. 3. Compatible with most phones. Compatible with a wide range of smartphone models compatible with iPhone, Samsung, LG, Sony, etc. 4. The phone holder is designed to be rotatable and movable to avoid pressing the volume button and power button during use. It also makes it easier to align your phone with the adapter, and you can focus as quickly as possible. 5. Full size 15 * 5.5 * 4cm. It is light and compact, easy to transport and store. This phone adapter is made of rubber and EVA. The aim was to hold your phone in place and protect it from scratches.